foo.cc: In function 'int Input(int*)':
foo.cc:5:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    5 |  int n; scanf("%d",&n);
      |         ~~~~~^~~~~~~~~
foo.cc:7:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    7 |   scanf("%d", &a[i]);
      |   ~~~~~^~~~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:29:15: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   29 |  int k;  scanf("%d", &k);
      |          ~~~~~^~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务